New chiral dimers consisting of a rod-like and cholesterol mesogenic units are reported to form a chiral twist-bend nematic phase (NTB *) with heliconical structure. The compressibility of the NTB phase made of bent dimers was found to be as large as in smectic phases, which is consistent with the nanoperiodic structure of the NTB phase. The atomic force microscopy observations in chiral bent dimers revealed a periodicity of about 50 nm, which is significantly larger than the one reported previously for non-chiral compounds (ca. 10 nm).

Do the short helices exist in the nematic TB phase?Dimeric compounds forming twist-bend nematic, Ntb, phase show unusual optical texture related to the formation of arrays of focal conic defects. Some of the focal conics show submicron internal structure with 8 nm periodicity, which is very close to that found in the crystalline phase of the material, suggesting surface freezing.

The fabrication of molecular structures with a desired morphology, e.g., nanotubes, nanoribbons, nanosprings, and sponges, is essential for the advancement of nanotechnology. Unfortunately, realization of this objective is expensive and complicated. Here, we report that irradiating a film comprising azobenzene derivatives with UV light produces oriented arrays of helical nanofilaments via the photoisomerization-induced Weigert effect. As a result, structural colors are observed due to the extrinsic chiral reflection in the visible wavelength range, and the reflected color can be tuned by adjusting the molecular length of the azobenzene derivative. This simple fabrication method can be used for fabricating large, reversible, and patternable color reflectors, providing a new platform for interference-based structural coloration as it exists in nature, such as morpho butterflies, green-winged teal, and various beetles.

The achiral liquid crystalline materials showing two B4 (HN) phases have been found to exhibit strong gelation ability for various organic solvents with reversible sol-gel phase transition. The gel is formed by helical tubules, which build entangled 3D network, encapsulating the solvent. The equilibrium of left- and right-handed tubules is preserved in the gel, even if the chiral solvent is used.

It is shown that the nanofilament structure of B4 made of azo-dimers can be easily re-structured by UV light.